Omicron-aryl alkylphosphonothioates



United States Patent 3,301,922 O-ARYL ALKYLPHOSPHONOTHIOATES John P.Chupp, Kirkwood, Mo., assignor to Monsanto Company, St. Louis, Mo., acorporation of Delaware No Drawing. Original application July 3, 1963,Ser. No. 292,741, now Patent No. 3,242,042. Divided and this applicationJune 7, 1965, Ser. No. 462,098

6 Claims. (Cl. 260-940) This application is a division of Serial No.292,741, filed July 3, 1963, and now US. 3,242,042.

This invention relates to new and useful O-aryl al-kylphosphonothioates.In addition this invention relates to insecticidal compositionscontaining at least one of these alkylphosphonothioates as an activeingredient.

The alkyl phosphonothioates of this invention can be represented by theformula (C 2)m wherein m and n are like or unlike integers from 0 to 1and wherein R is a lower alkyl radical (i.e. methyl, ethyl, propyl,butyl, amyl, and the various isomeric forms thereof containing up to andincluding carbon atoms).

These alkylphosphonothioates can be prepared by reacting3-chloro-4-cyanophenol with a halide or mixture of halides of theformula wherein R, m and n have the aforedescribed significance andwherein Z is a halogen of atomic number in the range of 16 to 36 (i.e..chlorine or bromine, preferably chlorine) in the presence of a hydrogenhalide scavenging agent or mixtures thereof (e.g. sodium carbonate,potassium carbonate, triethylamine, triisopropylamine, dimethylaniline,lutidine, l-pipecoline, pyridine, etc.) and the like in an amountsufficient to absorb the hydrogen halide by-product. Where and whendesired an inert organic liquid or solvent (e.-g. benzene, toluene,xylene, acetone, butanone, dioxane, etc.) can be used; While a Widerange of reaction conditions can be employed provided the system isfluid (i.e. a temperature above the freezing point of the system up toand including the reflux temperature of the system) it is preferred toemploy a reaction temperature in the range of from about 20 C. to about120 C. In general the halide reactant and 3-chloro-4-cyanophenol will beemployed in substantially equimolecular proportions. The scavengingagent can be added in an equivalent amount at the beginning of thereaction or throughout the course of the reaction.

As illustrative of the preparation of the alkylp-hosphonothioates ofthis invention but not limitative thereof is the following:

' Example I To a suitable reaction vessel equipped with a thermometer,agitator and reflux condenser is charged approximately 200 parts byWeight of benzene, approximately 4.0 parts by weight of3-chloro-4-cyanophenol, approximately 2.6 parts by weight oftriethylamine, and approximately 4.1 parts by weight of O-phenylmethylphosphonothionyl chloride. While agitating the mixture is heatedup to the reflux temperature and then refluxed for about five hours. Thereaction mass is then cooled to room temperature and then quenched withwater. The organic layer is separated and Washed first with aqueous 3%sodium carbonate and then with Water. The so-washed solution is thenstripped of volatiles under vacuum. The residue, a viscous oil, isO-phenyl O-(3- chloro-4-cyanophenyl) methylphosphonothioate.

Analysis.- Theory: 11.0% Cl, 9.93% S. Found: 11.78% Cl, 10.02 S.

Example 11 Employing the procedure of Example I but replacing O-phenylmethylphosphonothionyl chloride With a substantially equimolecularamount of O-phenyl n-butylphosphonothionyl bromide there is obtainedO-phenyl O-(3-chloro-4-cyanophenyl) n butylphosphonothioate which isinsoluble in water.

Example III Employing the procedure of Example I but replacing O-phenylmethylphosphonothionyl chloride with a substantially equimolecularamount of O-o-tolyl ethylphosphonothionyl chloride there is obtainedO-o-tolyl O-(3- .chloro-4-cyanophenyl) ethylphosphonothioate which isinsoluble in water.

Example IV Employing the procedure of Example I but replacing O-phenylmethylphosphonothionyl chloride with a substantially equimolecularamount of O-m-tolyl methylphosphonothionyl chloride there is obtainedO-m-tolyl O-(4- eyano-3-chlorophenyl) methylphosphonothioate which isinsoluble in water.

Example V Employing the procedure of Example I but replacing O-phenylmethylphosphonothionyl chloride with an equimolecular amount ofO-3,5-xylyl isoamylphosphonothionyl chloride there is obtainedO-3,5-xylyl O-(3-chloro- 4-cyanophenyl) isoamylphosphonothioate which isinsoluble in water.

Example VI Employing the procedure of Example I but replacing O-phenylmethylphosphonothionyl chloride with an equimolecular amount ofO-m-tolyl ethylphosphonothionyl chloride there is obtained O-m-tolylO-(3-chloro-4-cyan0 phenyl) ethylphosphonothioate which is insoluble inwater.

Example VII Employing the procedure of Example I but replacing O-phenylmethylphosphonothionyl chloride with an equimolecular amount of O-phenylisopropylphosphonothionyl chloride there is obtained O-phenylO-(3-chloro- 4-cyanophenyl) isopropylphosphonothioate which is insolublein water.

Example VIII Employing the procedure of Example I but replacing O-phenylmethylphosphonothionyl chloride with an equimolecular amount of O-phenylethylphosphonothionyl chloride there is obtained O-phenylO-(3-chloro-4-cyanophenyl ethylphosphonothioate which is insoluble inwater.

Example IX Employing the procedure of Example I but replacing O-phenylmethylphosphonothionyl chloride with an equimolecular amount of O-phenylisoamylphosphonothionyl bromide there is obtained O-phenylO-(3-chloro-4-cyanophenyl) ethylphosphonothioate which is insoluble inWater.

Example A Employing the procedure of Example I but replacing3-chloro-4-cyanophenol with an equimolecular amount of 4-cyanophenolthere is obtained O-phenyl O-(4-cyanophenyl) methylphosphonothioatewhich is insoluble in water.

Example B Employing the procedure of Example I but replacing O-phenylmethylphosphonothionyl chloride and 3-chloro- 4-cyanophenol respectivelywith an equimolecular amount of O-(2-chlor0ethyl) methylphosphonothionylchloride and 4-cyanophenol there is obtained O-(2-chloroethyl)O-(4-cyanophenyl) methylphosphonothioate which is insoluble in water.

Example C Employing the procedure of Example I but replacing O-phenylmethylphosphonothionyl chloride with an equimolecular amount ofO-n-propyl methylphosphonothionyl chloride there is obtained O-n-propylO-(3-chloro-4- cyanophenyl) methylphosphonothioate which is insoluble inWater.

The methods by which the alkylphosphonothioates of this invention areisolated will vary slightly with the reactants employed and the productproduced. Further purification by selective solvent extraction or byabsorptive agents such as activated carbon or clays can precede theremoval of the inert organic liquid or solvent when such is employed.Additionally an inert organic solvent can be added to and in thepurification by absorptive agents. However, the product is generallysatisfactory for insecticidal purposes without further purification.

It will be understood that the terms insect and insecticide are usedherein in their broad common usage to include spiders, mites, ticks, andlike pests which are not in the strict biological sense classed asinsects. Thus the usage herein conforms to the definitions provided byCongress in Public Law 104, the Federal Insecticide, Fungicide, andRodenticide Act of 1947, Section 2, subsection [1, wherein the terminsect is used to refer not only to those small invertebrate animalsbelonging mostly to the class Insecta, comprising sixlegged, usuallywinged forms, as beetles, bugs, bees, flies, and so forth, but also toother allied classes of arthropods whose members are Wingless andusually have more than six legs, as spiders, mites, ticks, centipedes,and wood lice.

The phosphonothioates of this invention are effective against a widevariety of insect pests. As illustrative of the activity but notlimitative thereof is the following:

A 1% by weight concentrate of the test chemical is prepared bydissolving the chemical in ml. of acetone. A 0.25 cc. tuberculin, B-DYale syringe is filled with the concentrate and placed in amicroinjection apparatus. The injector lever is pressed several times tomake certain that no air bubbles are trapped in the needle and theneedle is wiped with filter paper to remove any excess solution. Theinjector lever is pressed once to produce one microliter which isapplied directly to the ventral side of the abdomen of each of 10 plumcurculio, Conotrachelus ncnuphar. After application each insect isreleased Within observation dishes and held for 24 hours at roomtemperature and mortality observations made at the end of that time.This procedure is repeated at decreasing concentrations and the minimumconcentration in micrograms per adult to give 50% mortality determined.The following results were obtained:

Minimum conc. Test chemical: giving 50% mortality O-phenylO-(3-chloro-4-cyanophenyl) methylphosphonothioate 0.06 O-phenyl O (4cyanophenyl) methylphosphonothioate 0.32 O-(2-chloroethyl)O-(4-cyanophenyl) methylphosphonothioate 0.31 O (n propyl) O (3chloro-4-cyanophenyl) methylphosphonothioate 0.54

A 1% by weight concentrate is prepared by dissolving the test chemicalin 10 ml. of acetone. A 0.25 cc. tuberculin, B-D Yale syringe is filledwith this concentrate and placed in a microinjection apparatus. Theinjector lever is pressed several times to make certain no air bubblesare trapped in the needle and the needle is wiped with filter paper toremove excess solution. The injector lever is pressed once to produceone microliter which is applied directly to each of 12 lima bean leafdiscs 0.25 inch in diameter. Single second instar southern armywormlarvae (Prodenia eridania) are placed on each disc and the disc. encagedwith a plastic cap. After 48 hours at room temperature mortalityobservations are made. This procedure is repeated at decreasingconcentrations and the minimum weight concentration in micrograms perlarva giving 50% mortality determined. The results were as follows:

Minimum conc.

Test chemical: giving 50% mortality O-phenyl O-(3-chloro-4-cyanophenyl)methylphosphonothioate O phenyl O (4 cyanophenyl) methylphosphonothioate16.0

O-(2-chloroethyl) O-(4-cyanophenyl) methylphosphonothioate 23.0

Although the phosphonothioates of this invention are useful per se incontrolling a wide variety of insect pests, it is preferable that theybe supplied to the pests or to the environment of the pest or pests in adispersed form in a suitable extending agent.

In the instant specification and appended claims it is to be understoodthat the term dispersed is used in its widest possible sense. When it issaid that the phosphonothioates of this invention are dispersed, itmeans that particles of the phosphonothioates of this invention may bemolecular in size and held in true solution in a suitable organicsolvent. It means further, that the particles may be colloidal in sizeand distributed throughout a liquid phase in the form of suspensions oremulsions or in the form of particles held in suspension by wettingagents. It also includes particles which are distributed in a semi-solidviscous carrier such as petrolatum or soap or other ointment base inwhich they may be actually dissolved in the semi-solid or held insuspension in the semi-solid with the aid of suitable wetting oremulsifying agents. The term dispersed also means that the particles maybe mixed with and distributed throughout a solid carrier providing amixture in particulate form, e.g. pellets, granules, powders, or dusts.The term dispersed also includes mixtures which are suitable for use asaerosols including solutions, suspensions, or emulsions of thephosphonothioates of this invention in a carrier such asdichloro-difiuoromethane and the like fluorochloroalkanes which boilbelow room temperature at atmospheric pressure.

In the instant specification and appended claims it is to beunderstoodthat the expression extending agent includes any and all ofthose substances in which the phosphonothioates of this invention aredispersed. It includes, therefore, the solvents of a true solution, theliquid phase of suspensions, emulsions or aerosols, the semi-solidcarrier of ointments and the solid phase of particulate solids, e.g.pellets, granules, dusts and powders.

The exact concentration of the phosphonothioates of this inventionemployed in combatting or cont-rolling in sect pests can varyconsiderably provided the required dosage (i.e. toxic or lethal amount)thereof is supplied to the pests or to the environment of the pests.When the extending agent is a liquid or mixture of liquids (e.g. as insolutions, suspensions, emulsions, or aerosols) the concentration of thephosphonothioate employed to supply the desired dosage generally will bein the range of 0.00 1 to 50 percent by weight. When the extending agentis a semi-solid or solid, the concentration of the phosphonothioateemployed to supply the desired dosage generally will be in the range of0.1 to 25 percent by weight. From a practical point of view, themanufacturer must supply the agriculturist with a low-cost concentrateor spray base or particulate solid base in such form that, by merelymixing with water or solid extender (e.g., powdered clay or talc) orother low-cost material available to the agriculturist at the point ofuse, he will have an easily prepared insecticidal spray or particulatesolid. In such a concentrate composition, the phosphonothioategene-rally will be present in a concentration of 5 to 95 percent byweight, the residue being any one or more of the well known insecticidaladjuvants, such as the various surface active agents (eg detergents, asoap or other emulsifying or wetting agent), surface-active clays,solvents, diluents, carrier media, adhesives, spreading agents,humectants, and the like.

There are a large number of organic liquids which can be used for thepreparation of solutions, suspensions or emulsions of thephosphonothioates of this invention. For example, isopropyl ether,acetone, methyl ethyl ketone, dioxane, cyclohexanone, carbontetrachloride, ethylene dichloride, tetrachloroethane, hexane, heptaneand like higher liquid alkanes, hydrogenated naphthalenes, solventnaphtha, benzene, toluene, Xylene, petroleum fractions (e.g. thoseboiling almost entirely under 400 F. at atmospheric pressure and havinga flash point above about 80 F., particularly kerosene), mineral oilshaving an unsulfonatable residue above about 80 percent and preferablyabove about 90 percent. In those instances wherein there may be concernabout the phytotoxicity of the organic liquid extending agent a portionof same can be replaced by such low molecular weight aliphatichydrocarbons as dipentene, diisobutylene, propylene trimer, and the likeor suitable polar organic liquids such as the aliphatic ethers and thealiphatic ketones containing not more than about carbon atoms asexemplified by acetone, methyl ethyl ketone, diisobutyl ketone, dioxane,isop-ropyl ether, and the like. In certain instances, it is advantageousto employ a mixture of organic liquids as the extending agent.

When the phosphonothioates of this invention are to be supplied to theinsect pests or to the environment of the pests as aerosols, it isconvenient to dissolve them in a suitable solvent and disperse theresulting solution in dichlorodifluoromethane or like chlorofluoroalkanewhich boils below room temperature at atmospheric pressure.

The phosphonothioates of this invention are preferably supplied to theinsect pests or to the environment of the insect pests in the form ofemulsions or suspensions. Emulsions or suspensions are prepared bydispersing the phosphonothioate of this invention either per se or inthe form of an organic solution thereof in water with the aid of awater-soluble surfactant. The term surfactant as employed here and inthe appended claims is used as in volume II of Schwartz, Perry andBerchs Surface Active Agents and Detergents (1958, IntersciencePublishers, Inc., New York) in place of the expression emulsifying agentto connote generically the various emulsifying agents, dispersingagents, wetting agents and spreading agents" that are adapted to beadmixed with the active compounds of this invention in order to securebetter wet-ting and spreading of the active ingredients in the watervehicle or carrier in which they are insoluble through lowering thesurface tension of the water (see also Frear Chemistry of Insecticides,Fungicides and Herbicides, second edition, page 280). These surfactantsinclude the well-known capillary-active substances which may beanion-active (or anionic), cation active (or cationic), or non-ionizing(or non-ionic) which are described in detail in volumes I and II ofSchwartz, Perry and Berchs Surface Active Agents and Detergents (1958,lnterscience Publishers, Inc., New York) and also in the November 1947issue of Chemical Industries (pages 811-824) in an article entitledSynthetic Detergents, by John W. McCutcheon, and also in the July,August, September and October 1952 issues of Soap and Sanitary Chemicalsunder the title Synthetic Detergents. The disclosures of these articleswith respect to surfactants, i.e. the anion-active, cation-active andnonionizing capillary active substances, are incorporated in thisspecification by reference in order to avoid unnecessary enlargement ofthis specification. The preferred surfactants are the water-solubleanionic surface-active agents and the water soluble non-ionicsurface-active agents set forth in US. 2,846,398 (issued August 5,1958). In general it is preferred that a mixture of water-solubleanionic and water-soluble non-ionic surfactants be employed.

The phosphonothioates of this invention can be dispersed by suitablemethods (e.g. tumbling or .grinding) in solid extending agents either oforganic or inorganic nature and supplied to the insect pests environmentin particulate form. Such solid materials include for example,tricalcium phosphate, calcium carbonate, kaolin, bole, kieselguhr, talc,bentonite, fullers earth, pyrophillite, diatomaceous earth, calcinedmagnesia, volcanic ash, sulfur and the like inorganic solid materials,and include for example, such materials of organic nature as powderedcork, powdered wood, and powdered walnut shells. The preferred solidcarriers are the adsorbent clays, e.g. bentonite. These mixtures can beused for insecticidal purposes in the dry form, or, by addition ofwatersoluble surfactants or wetting agents the dry particulate solidscan be rendered wettable by water so as to obtain stable aqueousdispersions or suspensions suitable for use as sprays.

For special purposes the phosphonothioates of this invention can bedispersed in a semi-solid extending agent such as petrolatum or soap(e.g. sodium stearate or oleate or palmitate or mixtures thereof) withor without the aid of solubility promotors and/or surfactants ordispersing agents.

In all of the forms described above the dispersions can be providedready for use in combatting insect pests or they can be provided in aconcentrated form suitable for mixing with or dispersing in otherextending agents. As illustrative of a particularly useful concentrateis an intimate mixture of phosphonothioate of this invention with awater-soluble surfactant which lowers the surface tension of water inthe weight proportions of 0.1 to 15 parts of surfactant with sufficientof the phosphonothioate of this invention to make 100 parts by weight.Such a concentrate is particularly adapted to be made into a spray forcombatting various forms of insect pests by the addition of waterthereto. As illustrative of such a concentrate is an intimate mixture ofparts by weight of O-phenyl O-(3-chloro-4-cyanophenyl)methylphosphonothioate and 5 parts by weight of a water-solublenon-ionic surfactant such as the polyoxyethylene derivative of sorbitanmonolaurate.

Another useful concentrate adapted to be made into a spray forcombatting a variety of insect pests is a solution (preferably asconcentrated as possible) of a phosphonothioate of this invention in anorganic solvent therefor. The said liquid concentrate preferablycontains dissolved therein a minor amount (e.g. 0.5 to 10 percent byweight of the weight of the new insecticidal agent) of a surfactant (oremulsifying agent), which surfactant is also water-soluble. Asillustrative of such a concentrate is a solution of O-phenylO-(3-chloro-4- cyanophenyl) methylphosphonothioate in benzene whichsolution contains dissolved therein a water-soluble polyoxyethyleneglycol non-ionic surfactant and a water-soluble alkylaryl sulfonateanionic surfactant.

Of the surfactants aforementioned in preparing the various emulsifiable,wettable or dispersible compositions or concentrates of this invention,the anionic and nonsprayers, and spray clusters.

ionic surfactants are preferred. Of the anionic surfactants, theparticularly preferred are the well known watersoluble alkali metalalkylaryl sulfonates as exemplified by sodium decylbenzene sulfonate andsodium dodecylbenzene sulfonate. Of the non-ionic surfactants, theparticularly preferred are the water-soluble polyoxyethylene derivativesof alkylphenols (particularly isooctylphenol) and the water-solublepolyoxyethylene derivatives of the mono-higher fatty acid esters ofhexitol anhydrides (e.g. sorbitan). These materials in general contain15 to 30 moles of ethylene oxide per mole of the hexitol anhydride orthe alkylphenol.

In all of the various dispersions described hereinbefore forinsecticidal purposes, the active ingredient can be one or more of thecompounds of this invention. The compounds of this invention can also beadvantageously employed in combination with other pesticides, includingfor example, nematocides, bactericides, and herbicides. In this mannerit is possible to obtain mixtures which are effective against a widevariety of pests and other forms of noxious life.

In controlling or combatting insect pests the phosphonothioates of thisinvention either per se or compositions comprising same are supplied tothe insect pests or to their environment in a lethal or toxic amount.This can be done by dispersing the new insecticidal agent orinsecticidal composition comprising same in, on or over an infestedenvironment or in, on or over an environment the insect pests frequent,e.g. agricultural soil or other growth media or other media infestedwith insect pests or attractable to the pests for habitational orsustenance or propagational purposes, in any conventional fashion whichpermits contact between the insect pests andthe phosphonothioates ofthis invention. Such dispersing can be brought about by applying spraysor particulate solid compositions to a surface infested with the insectpests or attractable to the pests, as for example, the surface of anagricultural soil or other media such as the above ground surface ofplants by any of the conventional methods, e.g. power dusters, boom andhand Also for subsurface application such dispersing can be carried outby simply mix- 8 ing the new insecticidal agent per se or insecticidalspray or particulate solid compositions comprising same with theinfested environment or with the environment the insect pests frequent,or by employing a liquid carrier for the new insecticidal agent toaccomplish subsurface penetration and impregnation therein.

While this invention has been described with respect to certainembodiments, it is to be understood that it is not so limited and thatvariations and modifications thereof obvious to those skilled in the artcan be made without departing from the spirit and scope thereof.

What is claimed is:

1. An O-aryl alkylphosphonothioate of the formula wherein m and n areintegers from 0 to l and wherein R is lower alkyl.

2. An O-phenyl alkylphosphonothioate of the formula wherein R is loweralkyl.

3. O-phenyl O-(3-chloro-4-cyanophenyl) methylphosphonothioate.

4. O-phenyl phonothioate.

O-(3-chloro-4'cyanophenyl) ethylphos- 5. O-m-tolylO-(3-chloro-4-cyanophenyl) methylphos mcthylphos-

1. AN O-ARYL ALKYLPHOSPHONOTHIOATE OF THE FORMULA